


a fishy transformation

by writerinbrooks



Category: Haikyuu!!
Genre: Blowjobs, Falling In Love, First Time, Flirting, Fluff, GUYS I'M STILL BAD AT TAGS HELP ME PLEASE, M/M, Making Out, Mentioned Miya Osamu/Suna Rintarou, Merrow Sakusa, sexy times in chapter two
Language: English
Status: Completed
Published: 2020-07-22
Updated: 2020-11-12
Packaged: 2021-03-05 01:15:59
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 6,669
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/25445980
Author URL: https://archiveofourown.org/users/writerinbrooks/pseuds/writerinbrooks
Summary: "ATSUMU! GET YER ASS OUT HERE AND EXPLAIN WHY THERE'S AN ANGRY MERMAID IN THE FISH TANK!"A fanfic where Atsumu gets a little drunk and brings home a turtle (or so he thinks) to his and Osamu's shared flat.
Relationships: Miya Atsumu/Sakusa Kiyoomi
Comments: 39
Kudos: 434





	1. Chapter 1

**Author's Note:**

> uh honestly i don't know where this came from.

"ATSUMU! GET YER ASS OUT HERE AND _EXPLAIN_ WHY THERE'S AN ANGRY MERMAID IN THE FISH TANK!" Atsumu groaned, head pounding with a horrific hangover, and slowly sat up. He cursed quietly, squeezing his eyes shut as the world before him became blurry. He heard the sound of feet coming down the hallway before his door was wrenched open. Atsumu squinted at the blurry visage of his brother, and he figured that his twin was likely pissed.

Atsumu didn't really remember what happened. He was drunk, and he vaguely remembers rescuing a turtle that was trapped in plastic trash to bring it home and put it in the fish tank before he passed out. Osamu grabbed Atsumu by the back of his shirt, dragging him off the bed. Atsumu fell with a dull _thud_.

"'samu, you asshole. That hurt." Atsumu grumbled, struggling to free himself from his brother's grip and stand up. He had to stand still for a moment so he wouldn't nose-dive into the nearest corner of the wall.

"Don't call me fuckin' names, 'tsumu. Explain _why_ there's a _mermaid in the fish tank?"_ Atsumu groaned, shrugging helplessly. Mermaids existed - everyone in Japan knew that. They were extremely rare to come by, and had the sly ability to change their forms to another ocean animal.

Osamu eventually managed to drag his hungover brother into the main room to their shared flat. Sure enough, in their 85-gallon fish tank, was a mermaid. Or a merman. Male mermaid. It was too early for Atsumu to think straight, despite the fact that Osamu repeatedly told Atsumu he was convinced his brother was gay. _Does that have anything to do with this train of thought?_ Atsumu was jolted back into the presence when Osamu jabbed him in the side with his elbow.

The mer....thing was gorgeous - curly black hair framed an aristocratic face, dark eyes scanning the twins before it, pretty lips drawn down into a scowl. There were two moles above the mer-person's right eye, and like in the stories that Atsumu had heard, pale and fair skin. They were slim in figure, but there was an obvious power stronger than any human that rippled beneath the lean muscles. The mer-person's tail was a shimmering aquamarine blue, glinting iridescent colors in the water of the tank.

"Atsumu." Osamu hisses.

"Where'd the turtle go?" Atsumu blinked, and Osamu stared at him as if his brother was officially crazy. The mer-person lifted a hand and crooked a pointer finger at Atsumu in a _come here,_ gesture. Still hung-over and not entirely able to comprehend the situation completely, Atsumu shuffled closer.

The mer-person jerked Atsumu forward by the collar of his shirt, and the next thing Atsumu knew, he was being kissed. He felt his eyes widen, and stumbled back, blinking rapidly.

"Wh-" Atsumu started, but he was cut off.

"Why am I here?" The mer-person demanded. Even their voice, though angry, sounded beautiful, and Atsumu was forced out of daze again by his brother.

"I saved a turtle, not a mermaid." Atsumu said, dumbly.

"They can _shift_ , 'tsumu." Osamu hissed. Atsumu blinked.

"Ya got stuck in plastic." Atsumu replied.

"Why didn't you just leave me in the ocean? Released me somewhere else?" The mer-person flicked their tail, eyes narrowed.

"The area has a lotta plastic and you'd probably just get stuck again. I was also drunk, and I wanted a pet turtle." Atsumu yelped, head pounding as Osamu smacked him upside the head. "'samu, that _hurt_!"

"Good." Osamu clicked his tongue, turning to the mer-person. "I'm really sorry for my idiotic brother. The mer-person shrugged. "We can bring ya back to a cleaner part of the ocean today, if you'd like." The mer-person shook their head.

"I can't. In this form, I always need to be submerged at least halfway in water. I can survive in another form, say a goldfish in a bowl or a jar for a long period of time, but I'm too weak to change my form." The mer-person explained, dark eyes glaring at Atsumu, who lifted his hands up in defense. His head was starting to clear from his hangover, which was strange. It usually lasted at least a few hours. "A Merrow's kiss heals." The mer-person, now Merrow, spoke. "It also gains me the ability to speak your language."

The Merrow shifted uneasily in the tank, and that's when Atsumu noticed that the tank was _much_ too small for the Merrow to be in. Their bathtub wasn't much bigger, but it would be sturdier.

"Well... how do we bring ya back to the water?" Atsumu asked, shuffling on his feet.

"I need ocean water to regain my strength to shift forms." The Merrow explained. "I can stay in non-ocean water, but I'm really weak." Atsumu nods and heads over to the fish tank. Osamu already left to fill up the tub, likely knowing what his twin wanted to do. The Merrow looked cautious as Atsumu approached, stiffening slightly as Atsumu's arm slid behind the Merrow's bare back.

"How long can ya be out of water for in this form?" Atsumu asked.

"Five minutes."

"Alright." Atsumu lifted the Morrow, stumbling slightly under the initial weight before shifting his own. A small noise of shock escaped the Merrow, one strong arm banding itself around Atsumu's neck, holding on tightly. Osamu had the bathtub filling up with cold water, and the Merrow instantly wriggled free from Atsumu's grip to slip into the cold water.

"Do you have a name?" Osamu asked, tilting his head.

"Sakusa." The Merrow replied, sinking down into the tub.

"Is there a limited amount of time you can stay in non-ocean water?" Atsumu asked. Sakusa's expression turned pinched.

"I don't know." Atsumu and Osamu glanced at each other worriedly.

"Give me a few minutes, please." Osamu smiled pleasantly at Sakusa before he gripped Atsumu's wrist in an iron grip, dragging him out of the bathroom, closing the door behind him. "Are ya _fucking insane?"_ Osamu hissed, and Atsumu threw his hands up into the air.

"How was _I_ supposed ta know that the turtle was a _Merrow?"_

"Why did you bring a _turtle_ back home?"

"Why _wouldn't_ I?"

"I can hear you both," the twins heard Sakusa call plainly from the bathroom. Osamu shot Atsumu a look that said this isn't over yet, and shoved Atsumu towards the bathroom. Atsumu shrugged and pushed the bathroom door open, hopping up onto the counter to watch the Merrow swim back and forth.

"What do you eat?"

"Fish."

"So... like, fresh fish?" The deadpan look Sakusa shot him had Atsumu lifting his hands up in the air in surrender. "We'll figure out a way to get ya back to your home. I promise." Atsumu said, wringing his fingers together. "Sorry fer practically kidnappin' ya." Sakusa paused in what appeared to be stress-swimming, and stared at Atsumu.

"It's fine." Sakusa said, before he dipped back beneath the water. "Just bring me back home soon." Atsumu nodded, even though he knew that Sakusa wouldn't be able to see. "Are you two comfortable... with me in here?"

"Whaddya mean?" Atsumu blinked. "Ya look much more comfortable here than in the fish tank." Sakusa pointed to the shower, before tilting his head.

"Don't humans use that?" Atsumu nodded. "Are you connecting the dots?" Atsumu shook his head, and Sakusa sighed. "I thought humans were supposed to be smart." Atsumu's jaw dropped incredulously.

"Excuse me," Atsumu sputtered. "For yer information, I'm still tryin' to comprehend the fact that I brought back a _Merrow_ , and not a _turtle_." Sakusa snorted, and Atsumu felt his breath hitch at the pretty sound.

"He's asking if it's uncomfortable for us if he's in here if we shower." Osamu's voice came from the threshold, and Atsumu's lips parted in an "oh", then a slight flush took over his cheeks.

"Thought so." Sakusa smirked.

"Uh, I mean I don't mind showerin' in bathin' suits if I have ta." Atsumu shrugged, and Osamu shrugged one shoulder in return. "'m sure ya see plenty o' people in bathin' suits in the ocean."

"Unfortunately." Sakusa grumbled. "It's not like I'm going to be checking anyone out. I'll probably be sleeping to try to regain my strength." The twins glanced at each other as Sakusa dipped back beneath the water, swimming close to the floor of the tub before promptly curling up like a cat.

"Well. I'm going to make lunch. Atsumu, go out and get fresh fish." Atsumu barely caught the keys that Osamu threw at him. Atsumu shrugged, glancing once over his shoulder at Sakusa before he left the bathroom. He changed, combed his hair and brushed his teeth in their second bathroom before he left the flat.

Atsumu strongly disliked the fish market. The smell was overwhelming, and he quickly bought three large salmon and two tuna. It was pretty expensive, but it was a price Atsumu knew he had to literally pay for bringing home a Merrow. The smell of rice and curry was in the air as Atsumu returned to the flat with the fish.

Osamu greeted Atsumu with a nod, before he went back to talking on his phone. Atsumu guessed it was Suna, and that Osamu was trying to figure out how to keep the Merrow a secret. It wasn't a bad thing if Suna knew of the Merrow, everyone knew they existed. What would be a problem was that if a poacher, or hunter found out.

Not that they knew of any.

Almost as soon as Atsumu entered the bathroom after ice-boxing three of the five fish, Sakusa popped his head above the water's surface, dark eyes curious. He swam a little closer, and Atsumu noticed that the Merrow barely used his hands to swim, only his tail.

"I have one salmon. Not sure if it's enough." Atsumu said, lifting up the plastic bag. Sakusa pushed himself up on the edge of the tub to get closer. A little flustered at the sudden proximity with the gorgeous creature, Atsumu quickly took out the fish from the bag and handed them over. He was intrigued and slightly appalled when Sakusa bit off a third of the fish.

"My genetic make-up allows for me to eat them whole." Sakusa explained. "Merrows have stronger stomach acids." Atsumu felt his own stomach grumble, but he wanted to linger, to ask a few more questions. Sakusa seemed to sense that. "Go eat. Then you can ask me more questions." The Merrow's slender fingers wrapped around the last bit of salmon and shifted to sink back into the water to eat it. Atsumu headed back into the main room where Osamu was plating up the curry.

"So?" Osamu prompted as they both sat down to eat.

"Well, I don't know how much food he needs, but he just ate one whole 40kg salmon." Then, "what? I know they're hella expensive, but I got us into this mess. My job pays well enough so it's not that much of a loss."

"Yes, but how much does the Merrow eat?" Atsumu paused, spoonful of curry at his lips. Osamu rolled his eyes and Atsumu scowled, shoving the spoon into his mouth.

"I have an idea, 'samu." Atsumu grumbled. "Bokkun owns a pick-up truck, right? We could just buy an inflatable pool, fill it with water and load it onto the back. Then we take Sakusa and put him in the pool and drive to a cleaner beach. Boom."

"I'm assuming we'd have to do this in the dead of night." Osamu sighed.

"Yeah, but it's probably our safest bet."

"How do we get him to the water before his five minutes are up? The beaches around here are all rocky, and can't handle a pick-up driving too far down the roads to the water's edge. We can't lift an inflatable pool, physics doesn't work like that." Atsumu stared down at his plate of curry, feeling more and more disheartened with each word from his brother's mouth.

"'samu, stop makin' me feel more shitty than I already am." Atsumu grumbled, before he shoveled another few mouthfuls into his mouth as if to prevent his brother from talking further. Osamu merely sighed, but dropped the subject.

It had been nearly a week since Atsumu accidentally kidnapped a Merrow. He'd learned quite a bit about Sakusa since then, and his brother had stopped nagging him about how stupid all of Atsumu's ideas were to try to help Sakusa return to the ocean. Sakusa didn't eat too much - only every two or so days - and he hated loud noises.

He was polite and slept if one of the twins wanted to shower, though he did often pop his head over the edge of the tub when Atsumu wrapped a towel around his waist. Sakusa did it often enough that Atsumu had started to tease the Merrow.

_"Yer always poppin' yer head up when I'm done with my shower. Like what ya see?"_

Sometimes, the Merrow would simply rake his eyes over Atsumu's exposed body and shrug. Other times, Sakusa would smirk, prop his chin on his hand, and tilt his head to the side, teasing right back.

_"You always seem to be checking me out one way or another when we talk."_

Despite the many times that Atsumu asked Sakusa if he was uncomfortable here in the tub, often alone, the Merrow shook his head.

_"Don't ya wanna go home to the ocean?" A pause, then a small splash as Sakusa propped himself up on the side of the bathtub by his elbows._

_"I do." Sakusa replied. "But it's boring there." It's lonely, is what Sakusa doesn't say._

_"But the ocean is so vast, Sakusa! There must be so much to explore." Atsumu's gaze was so eager, so genuine that Sakusa couldn't bring himself to lie._

_"The ocean is vast, yes. But there are plenty of dangerous creatures out there. Traveling alone is the biggest mistake you can make." Sakusa remembered how he'd lost his cousin who'd foolishly disobeyed their herd's orders and ended up dying the the jaws of a Great White, which in turn, had obliterated Sakusa's entire family._

_He'd been the only one to escape. Atsumu seemed to notice the tense silence, and shuffled uneasily._

_"Why do ya wanna go back the ocean so bad if it's dangerous?" Atsumu asked._

_"It's the only home that I know."_

_"What if..." Atsumu began, before he trailed off. Sakusa tilted his head, waiting for the human to continue. Atsumu didn't, but an endearing flush crossed his face._

_"What if?" Sakusa prompted._

_"It's stupid." Atsumu shook his head._

_"You've already proven that you're stupid, saying something dumb won't change my mind." Sakusa rolled his eyes, and the flush turned into a blush as Atsumu stared at the Merrow incredulously. Sakusa felt the sudden, impulsive urge to kiss him._

_"What if this became a second home to ya?" Atsumu blurted, fingers wringing together. "I-I know that yer probably hatin' it here, and wanna go back to the ocean, but 'samu keeps shootin' my ideas down to figure out how ta return ya, and-"_

_"I wouldn't mind." Sakusa cut into Atsumu's nervous rambling, and the latter stared at him with wide golden-brown eyes. Sakusa felt that strange feeling in his chest again - a tightening, then a flutter. Atsumu's lips finally curled up into a smile, and Sakusa's felt his chest explode with a fluttering sensation._

_This isn't good._

"Yer fallin' in love with the Merrow." Osamu stated as they both got settled down in their beds. Atsumu shot his twin an incredulous look. "Yer always talkin' with him, ya smile and laugh a lot to the point where it's disgusting."

"Oi-" Atsumu protested, but was cut off immediately.

"Yer always comin' out of that bathroom with a dopey smile even though I know yer only talkin' with him, and Sakusa's a lot less prickly than when we first met him. Then again, we first met him in a _fish tank_ , so I don't know how accurate that statement is." Osamu shrugged. "Yer a lot brighter now, and ya blush way too easily 'round him. Or when you talk 'bout him."

"I do not!" Atsumu scowled, and Osamu's shit-eating grin broadened when he saw Atsumu's cheeks were red.

"Think about it." Osamu drawled, before he rolled over to leave Atsumu in a flurry of his panicked thoughts.

Atsumu knew that the he was attractive. He'd teased the Merrow a few times for staring at him when he'd only been wearing a towel around his waist. He'd felt hot beneath his skin, embarrassed and a little proud when Sakusa had taken the time to slowly and deliberately check out Atsumu, before he teased right back.

There was no doubt that the Merrow was gorgeous, and he readily admitted the fact whenever Sakusa teased him right back for it. The butterflies in his chest only got stronger. Atsumu rolled onto his side to stare at the wall.

Sakusa's impassive facial expression crossed his mind, the gentle slope from his neck to his shoulders, the Merrow's aristocratic features, and especially those two little moles above his right eye. Despite Sakusa's eyes being a rather flat dark color, Atsumu knew that they expressed so much more. Sakusa would often lay on the steps to the bath to be closer to Atsumu as the other sat on the counter - sometimes sitting on the edge of the tub with his legs in the water.

Atsumu knew that he couldn't deny being attracted to the Merrow for his physical appearance, there was something enchanting about the lean and powerful muscles that rippled beneath Sakusa's pale skin, the way that his tail moved when he swam. Atsumu still felt guilty when he saw Sakusa in the tub, swimming and sometimes pushing off of the walls. The Merrow deserved to be in a much more open space, in water where he could freely swim without any barriers.

Sakusa always told Atsumu to _shut up,_ or to _stop thinking_ whenever Atsumu furrowed his brow, a sure sign that he was blaming himself for Sakusa's current situation. _"I'm fine here, Atsumu." Sakusa would say, his voice oddly gentle._

The Merrow was kind, sarcastic and had occasional fastidious tendencies. He made Atsumu forget about his stupidly infuriatingly work clients and co-workers, he'd help Atsumu forget about his stressors so readily. When Atsumu asked why Sakusa was being so kind to him, even though he was trapped in a bathtub in a place he didn't know, Sakusa had shrugged.

_"I trust you. Besides, I find you intriguing." When Atsumu flushed, Sakusa had let out a little laugh, a sound that Atsumu had grown to love. "You're cute when you blush."_

_"'m hot, thank you very much."_

_"That too."_

Wait.

"'samu yer an asshole." Atsumu grumbled into his pillow, cheeks flooding with heat and slight mortification as he realized his brother was right. He was falling in love with Sakusa. His brother snorted in response.

"At least yer aware of it now."

The next day, Atsumu was working on filling up the tub with new water. Sakusa was currently in the shower beneath a spray of cold water in an attempt to keep him hydrated. Atsumu was just hosing down the floor of the tub to ensure it was completely clean when a spider skittered across the floor.

With a yelp, Atsumu reached up to grab onto the side of the tub, heaving himself up and over to higher ground. He ended up slipping, tumbling off the side and hitting his head against the tiles of the bathroom floor.

"Fuck!" Atsumu gasped, pain shooting through his head. He heard Sakusa's soft gasp, and suddenly cold hands were framing his face. "Wh-" Sakusa was hovering over him at an awkward angle given the Merrow had no legs. "Get back in the water, Sakusa. Yer gonna-"

"Shh." Sakusa insisted, and when he pulled one cold hand away, there was blood on the Merrow's fingers. "Go get your brother."

"Get back in the water." Atsumu retorted, cheeks flushed. He could only remember his brother's words from the night before, _yer fallin' in love with the Merrow._

"Not until you leave to get your brother." Sakusa shot back. Atsumu narrowed his eyes, and slowly reached for the side of the tub, stumbling to his feet. Sakusa stared up at him from his awkward position on the ground, and only dragged himself back in the direction of the shower when Atsumu left.

"'samu, I hit my head." Atsumu said as he walked into the living room, one hand on the wall and the other holding the cut on his forehead.

"Just go get ice." Osamu said from his position on the couch.

"'m bleedin'." Osamu looked up from where he was texting on his phone, and his eye widened slightly when he saw the blood speckles on Atsumu's shoulders and fingers. Osamu ditched his phone and forced Atsumu to sit down to treat the injury.

"What did you do?"

"Spider in the tub. Freaked out and slipped tryin' to get out." Atsumu grumbled, wincing as his brother cleaned the cut and dabbed at it with a disinfectant wipe from the medical kit.

"Well, it doesn't need stitches. But I'm putting a bandage and tape onto it." Osamu said. Atsumu nodded and pushed back his bleached bangs, letting his brother put the bandage on, grimacing at the feel of the tape. "Did you leave the water running?" Osamu asked, and Atsumu hummed.

"Yeah. Sakusa told me to find ya when he saw I got hurt." Osamu's lips parted to say something, but Atsumu cut him off. "Don't say anything please. Just... go finish fillin' the tub and put Sakusa in the water. He's just beneath the shower right now." Osamu wordlessly handed Atsumu an ice pack, and left.

Atsumu cleaned up the mess on the table, ice pack pressed to his head. A mere minute had passed before his brother's yell echoed through the flat again.

"ATSUMU! WHY IS THERE A NAKED HUMAN IN THE SHOWER?"


	2. Chapter 2

**Notes for the Chapter:**

> you see, i was gonna write more for this. then i opened the document, and skimmed through and noted that my writing style has changed a lot, and i couldn't be bothered to re-write it or add on when i had a decent-ish ending lmao.
> 
> nsfw/smut scene at the end~

Atsumu froze when he heard Osamu's bellow echo through the flat. His heart stuttered in his chest, his head spun with several different thoughts. He abandoned his job of cleaning up the table to hurry to the bathroom, ice pack still gently pressed to his temple. When he slid in through the doorway to the bathroom, his eyes widened.

True to Osamu's words, there  _ was  _ a naked human on the floor to the shower. The Merrow was no longer there, having been replaced by a human who looked eerily similar to Sakusa. Atsumu blinked, and the boy on the bathroom floor blinked back at Atsumu. The spray of the shower was shut off, and that's when the blonde realized that the other boy was shivering violently.

Atsumu hurriedly grabbed a towel, setting the ice pack down and crouching to wrap the towel around the boy's shoulders. Both Atsumu and Osamu helped the boy stand up on shaky legs, guiding him to settle him on the bathroom counter. The boy reached out and grabbed the ice pack, holding it out to Atsumu, who took it back.

"So...." Osamu started.

"I transformed." The boy stated in Sakusa's typical deadpan voice.

"So yer tellin' us that yer Sakusa?" Atsumu felt like his head was reeling. Whether it was from the dizziness of hitting his head earlier, or the information he'd been given, he wasn't sure.  _ First the turtle turning into a Merrow, and now said Merrow turning into a human? What's next? _ The boy nodded, pulling the towel closer to his body, teeth chattering.

"Oh. Here." Atsumu handed the ice pack over to his twin, before he stripped from his hoodie, holding it out to Sakusa, who stared at the fabric, before moving his gaze to stare wide-eyed at Atsumu. Atsumu stood there awkwardly, glimpsing Osamu's poorly concealed guffaw from his peripheral vision.

Sakusa reached out, cold fingers brushing against Atsumu's hotter skin, and curled them into the fabric. Atsumu had to help Sakusa pull it over his head, wrapping the towel around Sakusa's now-human waist. Sakusa nearly collapsed as soon as he stood.

"Yer probably not used ta havin' legs." Osamu commented. "We'll help ya out." 

"Thanks." Sakusa tipped his head, eyes falling shut as he slumped against Atsumu, who stumbled under his weight. As a human, Sakusa was a good couple inches taller than both twins, and it took the both of them to carry him to their shared bedroom. Sakusa was laid down on Atsumu's bed, and while Atsumu sifted through his drawers for something to lend Sakusa, Osamu went out to get some food prepared.

Sakusa was sound asleep, likely exhausted from his transformation, or something like that. Atsumu sat on the edge of the bed, after having found a pair of boxers and sweatpants, settling them on the nightstand. Sakusa was still as pretty in his human form as he was in his Merrow form, and Atsumu couldn't resist the urge to gently brush back the wet curls sticking to the other's forehead.

Sakusa looked cute in his hoodie - it was a little baggy on his lithe form, given that Atsumu was a well-built and broad professional athlete (who was on summer holiday, thank you very much). Atsumu got a glass of water, and left to enter the living room slash dining room slash kitchen, where Osamu was preparing what looked like yakisoba. 

"Any ideas how he turned from a Merrow to a human?" Osamu asked, glancing briefly at Atsumu as he sat down at the kitchen counter, throwing back a glass of water. Atsumu shook his head, before wincing briefly at the throbbing in his head. He reached up, pressing a few gentle fingers against the bandage. "Too bad Sakusa can't kiss it better." Osamu grinned, and Atsumu flipped him off with a noncommittal grunt.

The twins remained in silence until it was time to eat. They decided not to disturb Sakusa, instead keep a portion for him later in case he got hungry, and ate their lunch. It wasn't until a few hours later, after Osamu had left to go visit Suna, that Atsumu heard a shuffling noise, then a loud  _ thump _ come from his room.

Atsumu hurried into his bedroom to find a disoriented Sakusa on the ground, towel unraveled so he was practically naked from the waist down. Atsumu forced his eyes to stay above Sakusa's shoulders.

"You a'ight?" Atsumu asked, crouching to offer Sakusa a hand. Sakusa blinked, before nodding.

"It's a little weird." Sakusa replied quietly, allowing Atsumu to pull him up and help him get fully dressed. "My vocal chords feel different. This feels different," he added, gesturing to himself. "Especially this." Sakusa finished, pointing between his legs, and Atsumu choked on his own breath. 

"That's-" Atsumu began, before he stopped completely. "Merrows don't have reproductive organs?" Sakusa shrugged in response.

"Probably."

"What do ya mean probably?" Atsumu sputtered.

"We probably do, but I personally don't care. I don't find it appealing." Sakusa explained as Atsumu led Sakusa out to the living room. Atsumu hesitated, curious to know what Sakusa meant, but not wanting to push further. "You can ask, you know." Sakusa sounded amused, letting out a soft grunt as Atsumu settled him down on a couch.

"I will. But first, are ya hungry?" 

"A little bit." Sakusa admitted.

"We have some noodles that 'samu just made. Ya can't eat like ya did when you were a Merrow." Atsumu said, meandering his way back in the kitchen to pop the third plate of yakisoba from the fridge into the microwave. "How are ya feelin'?"

"Weird." Sakusa replied. "It's strange not to be in water all the time." Atsumu watched from the kitchen as Sakusa lifted his legs, then his hands, as if searching for something. Sakusa glanced over the edge of the couch, blinking when he realized Atsumu was watching him. A pretty flush reached his cheeks, and  _ oh _ it was the first time Atsumu had seen Sakusa blush. He liked it, Atsumu decided.

"Yer also cute when ya blush." Atsumu's lips quirked up into a grin, and Sakusa's hands covered his cheeks, eyes wide. "Looks like Merrows couldn't blush, but now ya can." Sakusa's lips curved down into a petulant pout, disappearing from view as he fell back onto the couch. Atsumu snickered, and turned as the microwave dinged, taking out the plate and a fork, presuming that chopsticks might be a little too much for now.

Atsumu then spent the next five minutes trying to teach Sakusa how to use a fork, inevitably giving up and feeding Sakusa himself. Sakusa looked pleased with the yakisoba, and gratefully took the glass of water that Atsumu offered him. 

"You still want to ask your question?" Sakusa asked after Atsumu had cleaned up, settling himself back down on the couch. Atsumu stared at him, confused. Sakusa stared back, unblinking.

"Oh. Right." Atsumu tilted his head to the side. "Ya said ya didn't find reproductin' appealing. Ain't that the whole point of keepin' the Merrow population from goin' extinct?" Sakusa shifted, burrowing deeper into Atsumu's hoodie before he replied, voice muffled.

"Merrows only engage intimately if the sole purpose is to reproduce. Unlike humans, who seem to have the need to do it  _ everywhere _ ." Sakusa's expression twisted down into one of such disgust that Atsumu had to bite back the snort threatening to escape his lips. 

"There weren't too many females in the clan, and even then, none of them drew my interest. No females from other clans drew my interest either, despite my family insisting that I needed to find a... mate." Again, Sakusa's nose scrunched up, and this time Atsumu couldn't help the bark of laughter.

"What?" Sakusa looked ruffled, cheeks red and lips turned down into a frown.

"Nothin', nothin'," Atsumu grinned. "Yer as prickly as a sea urchin. Continue." Sakusa looked reluctant to, especially after Atsumu's laughing fit. 

"Right..." Sakusa started. "Anyways, I just thought that something was wrong with me, since I never even thought about reproducin' just to help my species, let alone start a family." Sakusa's brow furrowed, before his gaze darted up to rake over Atsumu's features. "Well, that's what I thought, until I met you." The last part is mumbled so softly Atsumu almost didn't catch it.

"I- what?" Atsumu's jaw had dropped, staring at Sakusa with a flush riding high on his cheeks. "Hold on," Atsumu's head spun, and this time he knew why. "Yer sayin' that ya weren't ever interested in reproducin' or bein' intimate with anyone until ya met me?" Sakusa's cheeks flushed, and he shoved his face further into Atsumu's hoodie.

"Don't say it like  _ that _ ." Sakusa grumbled. "But yes." Sakusa scrubbed a hand across his face while Atsumu sat at the other end of the couch dumbly, stunned. "Besides, I'd never kissed anyone before you." Sakusa added, tugging at the strings of Atsumu's hoodie. "I'm sorry, this is probably really wei-"

Sakusa was cut off as a pair of lips pressed to his, a warm and calloused hand gently tilting his head up. The newly-turned human gasped, hands instinctively reaching up to rest on broad shoulders, not quite sure whether he wanted to push or pull the other. Atsumu's lips were soft and warm, the kiss sweet and delicate, a stark difference to their first forced kiss. When Atsumu made a move to pull back, an embarrassingly loud whimper left Sakusa's lips, and he felt Atsumu grin against his mouth.

"Don't be so cocky." Sakusa mumbled, pulling Atsumu closer by sliding his arms around his neck.

"Yessir." Atsumu breathed, before he kissed Sakusa with smiling lips. The heat that was flooding through Sakusa's veins was something quite unfamiliar to him, but he couldn't say that he didn't like it. Sakusa's breath hitched when he felt a strong arm wind around his waist, pulling him to sit in Atsumu's lap, the latter tilting his head up as Sakusa gained height on him. 

Everything below Sakusa's waist was different, he didn't understand it - especially not the heat that curled in his gut, the strange discomfort he felt between his legs. A soft whimper escaped Sakusa's lips as he inched forward, Atsumu readily accepting Sakusa's close proximity.

"Atsumu," Sakusa breathed, and Atsumu pulled back slightly, resting their foreheads together. Atsumu's lips were red and swollen, tongue swiping across his lower lip, eyes half-lidded and something dark swimming behind his gaze. Their breathing was heavy, almost harsh, and a buzz from Atsumu's phone broke them from their daze.

Atsumu grumbled something beneath his breath and shifted to grab it. As he did, Sakusa felt a hardness press against him, and felt Atsumu's breath hitch when he shifted forward.

"Who is it?" Sakusa asked, shifting to try to look.

"Osamu." Atsumu replied. "He said he's stayin' with Suna for the night." Atsumu's cheeks were tinted a slight red as he turned back to face Sakusa, before a small smile crossed his lips, reaching up to cup Sakusa's cheeks. "I know ya said that Merrows aren't big in'ta intimate stuff, and I know ya said that humans always have the urge to do it, 'n I'm a little..." Atsumu shifted, cheeks red. "We can stop now, if ya want-" Sakusa shook his head, worrying his lower lip between his teeth almost anxiously.

"Show me," Sakusa said softly, watching Atsumu's throat bob. "I trust you." Atsumu's lips parted slightly, and he stared up at Sakusa with wide golden-brown eyes. Sakusa made the first move and dipped his head to kiss Atsumu again, who eagerly accepted Sakusa's awkward kiss. 

"I'll teach ya whatever ya wanna know about yer new body." Atsumu purred, his voice husky. A pleasant shiver ran down Sakusa's spine, and he bit back a low groan as Atsumu's hot hands slipped beneath the fabric of the hoodie he was wearing, stroking pale and soft skin. Sakusa found himself arching into Atsumu's touch, lips parting on a gasp. 

Something wet slipped into Sakusa's mouth, and a surprised noise left him, causing him to nearly pull back. Atsumu's hand curled into Sakusa's hair, keeping him in place gently, and pressed deeper into Sakusa's mouth with his tongue. Tentatively touching his tongue to Atsumu's, a groan left the both of them, and their kiss grew deeper. Sakusa's world was tilted as Atsumu laid him down on the couch, licking deeper into his mouth.

Sakusa's legs shook against Atsumu's hips, allowing the blonde to press himself up against the length of Sakusa's body. Sakusa didn't know where to touch, where to move or what to do next. His hands were curled in the fabric of Atsumu's shirt, trying to follow the hungry movements of Atsumu's mouth, the way his hips rolled forward.

Hands slid down to cup two globes of flesh on Sakusa's body, and he jolted forward with a soft gasp. Atsumu pulled back from their heated make-out, a string of saliva connecting their lips together.

"Such a firm and pretty ass," Atsumu groaned, kneading the flesh and Sakusa pushed back into the touch, a needy whimper escaping his throat. "Look at ya, so perfect n' gorgeous." Sakusa blushed, and shifted as he allowed Atsumu to tug the hoodie over his head. "Ya know," Atsumu began in a slow drawl, raking his eyes over the exposed flesh. "'m gonna make you see stars."

Before Sakusa could demand to know what Atsumu meant by that, the blonde had lowered his head to trail hot and wet kisses down his neck, before taking a nipple into his mouth. Sakusa's arms wrapped around the back of Atsumu's neck on reflex, gasps and soft whimpers spilling from his lips. He felt as if fire was flooding through his veins, and briefly thought that  _ I was never told intimacy was supposed to feel this good _ . Or perhaps it was only with Atsumu that he felt this way.

Atsumu's mouth was hot and wet as it sucked, licked and nibbled at his nipple, his fingers rolling and pinching the other one on Sakusa's chest. The discomfort between Sakusa's legs had turned into an ache, and he whimpered, squeezing his thighs against Atsumu's hips. Something in his head was begging for pressure, or some sort of relief.

"Atsumu," Sakusa gasped, rolling his hips up desperately. Atsumu pulled off of Sakusa's nipples, and trailed hot kisses down his abdomen until it reached the waistband of the borrowed sweatpants. In one swift movement, Atsumu had pulled them off, revealing a bulge between Sakusa's legs. The moment that Atsumu brushed his lips over it, Sakusa threw his head back with a soft moan.

"This," Atsumu purred, "is yer cock." He pressed a gentle kiss to it, and something Sakusa now recognized as pleasure shot through his body. "Now, I dunno 'bout Merrow anatomy, but fer us humans, we can use this ta reproduce." Atsumu mouthed over the bulge, and Sakusa couldn't bite back the needy whine, hips stuttering up. 

Atsumu's hand came down to press against Sakusa's hip, arching a single brow and Sakusa stilled in his movements. Atsumu then pressed the flat of his tongue against the bulge, and Sakusa practically keened, throat bobbing as Atsumu tortured the sensitive spot between his legs.

"Atsumu, please." Sakusa gasped. Atsumu exhaled softly, before he hooked his fingers beneath the waistband, tugging the boxers off. Sakusa watched, cheeks red, as his...  _ cock _ sprung free, slapping against his abdomen with a wet sound. It felt heavy between his legs, and the tip of it was shiny and red. Atsumu wasted no time in licking a stripe from the base of his cock to the tip, pressing it to Sakusa's abdomen before he wrapped his lips around it.

Pure bliss. Sakusa's eyes fluttered shut, pleasure sparking every nerve in his body, body trembling as Atsumu's mouth slid further down his cock. When Atsumu hummed, Sakusa's body nearly jackknifed up off the couch as the vibrations caused a pulsing sensation. Atsumu's hand reached between his legs, parting them further. There was a slight gagging noise, but Sakusa's worry dissipated as he felt Atsumu's throat muscles constrict around his throbbing cock.

It wasn't long before Sakusa felt like he was reaching the last shred of his self-control, body tensing before his cock kicked, twitching in Atsumu's mouth. Sakusa felt boneless, tired as he fell back on the couch, sweat coating his body. Atsumu still had his mouth wrapped around Sakusa, swallowing before pulling off. Sakusa trembled softly as Atsumu gently lapped at Sakusa's now limp and spent cock on his stomach, cleaning up the remaining white substance.

"What..." Sakusa mumbled, too out of it to form coherent words. Atsumu sits back on his heels, a bulge tenting his own sweatpants up, before wiping his mouth.

"'scalled an orgasm." Atsumu said, pressing a sticky kiss to Sakusa's hip, causing the other to squirm slightly. 

"What about you?" Sakusa asked, eyes half shut. Atsumu hummed, and Sakusa forced his eyes open.

"I'm gonna go brush my teeth first, and get a wet towel to clean ya off." Atsumu said, voice gentle. Sakusa nodded, and let out a shuddering breath when he heard Atsumu leave. A few minutes later, he felt Atsumu's return, and warm and wet cloth dragged across Sakusa's sensitive skin, and his eyes fluttered open.

"I want a kiss." Sakusa mumbled, and Atsumu grinned, leaning forward to press their lips together. Atsumu tasted like mint. Sakusa shifted, feeling a little awkward completely naked, but Atsumu scooped him up in his arms, carrying him back into the bedroom.

"I'll clean up the clothes later." Atsumu breathed, and Sakusa nodded, pulling Atsumu close for another kiss.

It was almost a strange feeling, having someone else's lips on yours, their warmth enveloping you and making you feel cozy inside. Sakusa had thought this would never happen to him, yet here he was, glad that Atsumu had brought him home. 

**Author's Note:**

> many fishy transformations (you decide whether the pun is intended or not)
> 
> a turtle to a merrow, then a merrow to a human? owo
> 
> [my twitter](https://twitter.com/writerinbrooks)


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